Sustained high output release of Nitric oxide (NO) as result of activation of inducible nitric oxide synthase (iNOS), and increased production of the antiproliferative/profibrotic cytokine transforming growth factor-beta1 (TGF-beta1) are well documented in glomerulonephritis. Modulation of iNOS activity and of TGF-beta1 production can therefore be viewed as anti-inflammatory strategies. The present study employed all-trans retinoic acid (atRA) which is known to have anti-inflammatory effects and to modulate expression of iNOS and TGF-beta1, in order to explore its effect on iNOS enzyme activity and TGF-beta1 production in anti-GBM antibody induced glomerulonephritis. Glomerulonephritis was induced in Lewis rats by injection of anti-GBM antibody. A group of nephritic rats were given daily administration of atRA for 14-16 days. Extent of proteinuria was assessed by measuring urine protein and creatinine excretion. iNOS enzyme activity was measured by calculating conversion of L[14C]arginine to L-[14C]citrulline in glomerular protein lysates. Levels of TGF-beta1 in glomerular protein lysates were measured by quantitative ELISA. Levels of proliferating nuclear antigen (PCNA), TGF-beta receptor II (TGFbeta-RII), and fibronectin were assessed by Western blot analysis. Glomerular iNOS activity in atRA treated nephritic animals was attenuated in comparison to that in nephritic controls that were not. Glomerular expression of PCNA was also reduced. Levels of TGF-beta1 were increased in glomeruli of atRA treated nephritic animals. In these animals, there was no change in glomerular levels of TGF-beta receptor II (TGFbeta-RII) or fibronectin. and there was no reduction in urine protein excretion. These results suggest that atRA attenuates iNOS activity and proliferation in glomeruli of nephritic animals. The failure of atRA treatment to reduce proteinuria could be due to the increase in TGF-beta1 levels and to inhibition of iNOS-driven NO production.

Objective: Approximately 30% of preeclamptic pregnancies exhibit abnormal liver function tests. We assessed liver injury-associated enzyme levels and circulating transforming growth factor beta (TGF-β) levels in an arginine vasopressin (AVP)-induced pregnant Sprague-Dawley rat model.Methods: Pregnant and non-pregnant Sprague-Dawley rats (n=24) received AVP (150 ng/hr) subcutaneously via mini-osmotic pumps for 18 days. Blood pressure was measured, urine samples were collected, and all animals were euthanized via isoflurane. Blood was collected to measure circulating levels of TGF-β1-3 isomers and liver injury enzymes in pregnant AVP (PAVP), pregnant saline (PS), non-pregnant AVP (NAVP), and non-pregnant saline (NS) rats. Results: The PAVP group showed significantly higher systolic and diastolic blood pressure than both saline-treated groups. The weight per pup was significantly lower in the AVP-treated group than in the saline group (p<0.05). Circulating TGF-β1-3 isomer levels were significantly higher in the PAVP rats than in the NS rats. However, similar TGF-1 and TGF-3 levels were noted in the PS and PAVP rats, while TGF-2 levels were significantly higher in the PAVP rats. Circulating liver-type arginase-1 and 5'-nucleotidase levels were higher in the PAVP rats than in the saline group. Conclusion: This is the first study to demonstrate higher levels of TGF-β2, arginase, and 5'-nucleotidase activity in PAVP than in PS rats. AVP may cause vasoconstriction and increase peripheral resistance and blood pressure, thereby elevating TGF-β and inducing the preeclampsia-associated inflammatory response. Future studies should explore the mechanisms through which AVP dysregulates liver injury enzymes and TGF-β in pregnant rats.

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Conclusions:The CTGF vaccine has the potential to prevent the progression of renal fibrosis and delay the deterioration of renal function with a low frequency of administration. Thus, this CTGF vaccine could be a promising preventive strategy for CKD patients.